ENTRAINED-FLOW CHLORINATION OF ILMENITE TO PRODUCE TITANIUM TETRACHLORIDE AND METALLIC IRON

The reaction of FeCl2 vapor with TiO2 in ilmenite to yield TiCl4 and metallic iron was studied at 1523 to 1723 K in an entrained-flow reactor. Ilmenite/carbon mixtures containing carbons with internal surface areas from 1 to 600 m2/g were milled to various average particle diameters ranging from 6 to 65-mu-m. Up to 44 pct of the stoichiometric FeCl2 reacted at the highest retention time of 34 seconds when a sixfold excess of FeCl2 vapor was used. Maximum experimental reaction yields were only about two thirds of the theoretical yield calculated for equilibrium conditions. For large particles, a negative effect of temperature on reaction rate indicated that the reaction rate was controlled by ash layer diffusion resistance. For small particles, under the higher turbulence conditions, the early stages of reaction appear to be influenced by film mass transfer.